 /*******************************************************************************
  * Copyright (c) 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.runtime.preferences;

 import java.util.Map ;

 /**
  * Preference filters are used to describe the relationship between the
  * preference tree and a data set when importing/exporting preferences.
  * <p>
  * For instance, a client is able to create a preference filter describing
  * which preference nodes/keys should be used when exporting the
  * "Key Bindings" preferences. When the export happens, the tree is
  * trimmed and only the applicable preferences will be exported.
  * </p>
  * <p>
  * Clients may implement this interface.
  * </p>
  *
  * @since 3.1
  */
 public interface IPreferenceFilter {

     /**
      * Return an array of scopes that this preference filter is applicable for. The list
      * of scopes must not be <code>null</code>.
      * <p>
      * For example:
      * <code>new String[] {InstanceScope.SCOPE, ConfigurationScope.SCOPE};</code>
      * </p>
      *
      * @return the array of scopes
      */
     public String [] getScopes();

     /**
      * Return a mapping which defines the nodes and keys that this filter
      * applies to.
      * <p>
      * If the map is <code>null</code> then this filter is applicable for all
      * nodes within the scope. The map can also be <code>null</code> if
      * the given scope is not known to this filter.
      * </p>
      * <p>
      * The keys in the table are Strings and describe the node path. The values are
      * an optional array of {@link PreferenceFilterEntry} objects describing the list of
      * applicable keys in that node. If the value is null then the whole node is
      * considered applicable.
      * </p>
      * <p>
      * key: <code>String</code> (node)<br>
      * value: <code>PreferenceFilterEntry[]</code> or <code>null</code> (preference keys)<br>
      * </p>
      * <p>
      * For example:
      * <pre>
      * "org.eclipse.core.resources" -> null
      * "org.eclipse.ui" -> new PreferenceFilterEntry[] {
      * new PreferenceFilterEntry("DEFAULT_PERSPECTIVE_LOCATION"),
      * new PreferenceFilterEntry("SHOW_INTRO_ON_STARTUP")}
      * </pre>
      * </p>
      *
      * @return the mapping table
      * @see PreferenceFilterEntry
      */
     public Map getMapping(String scope);

 }

